Bike Tech Tip – Play with your bike


No, no… I don’t mean dress up your bike in a fancy little frock and have a tea party or play date, nor do I mean having a very “special” relationship with your Specialized while your roommate is out. I mean that annoying wiggle and shake you get when things aren’t as tight as they should be.

Where might you find play on your bike? The most likely culprits are your headset, hubs, bottom bracket and brakes. Basically anyplace you have bearings… and your brakes.

How do you check for play? Let’s start from the bottom and work our way up.

Bottom Bracket:

This is the largest bearing on your bike. It has the most torsional force on it of any of the bearings since this is where you’re really cranking down to power the bike forward and up those hills. Since this part of the bike twists so much, the BB can loosen up if it or your cranks aren’t tight enough. Grab your crank arms and shake them back and forth. If they clunk and thunk and make otherwise less than friendly noises your BB is too loose. Now take the chain off your rings and see if the crankarms spin freely. If they don’t, then your BB is too tight. To adjust it you’ll need special tools, so either ease on down to your LBS and ask them to take care of it – you may want them to pull it apart, clean it all out and then put it back together since a lot of grit and grime can get in there as it’s so close to the ground – or give us a bell and a bottle of wine and if we have the tools for your BB, we’ll make it happen.

Hubs:

Your hubs spin more than any part on your bike – well… maybe a little bit less than your head might be spinning the morning after a proper knees-up team awards dinner, but hubs can be a bit of a bugger to adjust. If your hubs are too tight, they won’t spin freely and you’ll be wasting energy. If they are too loose, they’ll have side to side movement which will make the bike not handle properly, especially at high speeds and going into turns.

Pick your bike up and grab the wheel. Spin the wheel so that the valve is at the 3 o’clock or 9 o’clock position and let it go. The wheel should spin by itself and the valve will settle at the bottom. If the wheel doesn’t spin, your hubs are too tight. If the wheel spins, hooray! The bearings in your hubs aren’t too tight! Now, if the wheel spins, grab the wheel and give it a shake side to side. If you feel some wiggle, then your hubs are too loose.

How to fix it: Unfortunately there are way too many different hub designs out there and no one-size-fits-all method, so ask your good buddy Google how to loosen and tighten your particular brand and model of hubs. You’ll know they’re the right tension when the wheel spins freely and there is no more side to side movement when you try to wiggle it.

A special note: Check your hubs for play while the wheels are on the bike and the quick releases are closed tightly. Quick release hubs use hollow axles which compress slightly when you tighten the QR skewer, causing the bearings to tighten up. This means that if you adjusted your hubs like Goldilocks to be just right with the wheels off the bike, they will be too tight once you tighten the QR. Wheels off the bike should have a tiny amount of play which will disappear when you put them back on your trusty steed.

Brakes:

This is the one part where we’re not checking on bearings. Grab your brakes and shake them a little to make sure they are properly and firmly attached to the frame. If they don’t wiggle, you’re fine. If they do wiggle a bit, grab your size 5 allen key, make sure the brakes are centered and tighten the brake bolt behind the fork or on the brake bridge until they don’t move anymore.

Wow! that was easy!

Headset:

Your headset is the bearing – well, the two bearings on your bike that are under the most pressure, but turn the least – which is never good for bearings. Assuming you’ve already checked your hubs and brakes for play, grab your bike, wheels on the ground and squeeze your front brake. Now, front brake on and gripping the handlebars, try to rock the bike forwards and backwards, pushing downwards slightly. If you feel the infamous thunk in the form of a hard stop when you’re pushing in either direction, then yes, you got play. If you don’t have play, pick up the front end of the bike and turn the handlebar left and right. It should spin smoothly with a light touch and with no stops anywhere. If the headset is too tight you may be the victim of “indexed shifting” where the handlebar seems to stick in the middle of the turn or it turns in “indexed” steps. Because the headset bearings are under constant pressure without spinning and also get to absorb any shock and awwwww and vibration in your fork, the bearings can actually create little dimples in the races or cups. As the bearings turn, they then “click” into the dimples they have created.

mmmm… dimples…

[cml_media_alt id='57655']Cheryl[/cml_media_alt]

Thanks for the demonstration, Cheryl, but that’s not quite what I meant.

[cml_media_alt id='57656']Dimples[/cml_media_alt]

Ah, that’s better.

Fortunately the headset is pretty easy to fix. Most people have integrated or at least threadless headsets nowadays, so all you need to do is loosen the top cap screw on the top of the steertube and the 1, 2 or 3 pinch bolts that are on the side of the stem, clamped around the steertube.

[cml_media_alt id='57657']Headset, steertube, stem[/cml_media_alt]

Once all this is loose, tighten the top screw to the point that  there is no more play in the headset. Just to be sure now, pick up the front end of the bike and drop it back down firmly but without slamming it, holding the handlebars near the middle. Double check for play and adjust accordingly. Lastly, make sure your handlebars are straight and tighten up on the pinch bolts. Make sure you follow torque specs if you have a carbon steertube! The last thing you want to do is crush that puppy.

Voila! Your bike should now have no more play and you should get your shoes on and go out and play with your bike… or bring it on the Steve Allen Show and play your bike like Frank Zappa.

No, I’m not putting up a picture of Frank Zappa’s lower back dimples, but i will give you a picture of him in a frock.

[cml_media_alt id='57658']Zappa[/cml_media_alt]

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